Carlson, DA; Offor, II; El Messoussi, S; Matsuyama, K; Mori, K; Jallon, J-M

Journal of Chemical Ecology [J. Chem. Ecol.], vol. 24, no. 9, pp. 1563-1576, Sep 1998

Study of lipids from male and female laboratory-reared flies led to the demonstration of a potent contact sex stimulant in extracts and cuticular hydrocarbons of the female tsetse fly Glossina tachinoides (Westwood) against conspecific males. Thin-layer and column chromatography indicated that extracts contained hydrocarbons and saponifiable lipids. Biological activity was found in the alkanes from females, including prominent branched-chain alkanes that were detected by gas chromatography (GC). The alkanes were separated and collected by preparative gas chromatography (GC), and only the 37-carbon region showed biological activity. GC-mass spectrometry showed the major peak contained a mixture of isomeric 11,23-, 13,25- plus a minor amount of 11,21-dimethylheptatriacontane. Two racemic isomers were synthesized, and bioassays showed that the greatest activity was possessed by the 11,23- isomer with somewhat less activity in 13,25-dimethyl heptatriacontane. Dose-response data showed ED sub(50) at 5 mu g per decoy with solvent-washed males, nonspecific females, or corks as decoys. These alkanes released sexual activity in males that comprised most of the behaviors released by a female fly of the same species.